Open and closed-loop control devices, including software, for plants for the heat treatment of workpieces made of metal; Plants for the heat treatment of workpieces made of metal, essentially consisting of at least one furnace for the heat-up of workpieces, in particular under protective or reactive atmospheres, and with at least one cooling or quenching facility;; industrial furnaces; parts of the goods listed, in particular for holding, transporting and supporting the workpieces; cooling, ventilation and drying facilities; Construction, installation of heat treatment plants and industrial furnaces; commissioning of heat treatment plants and industrial furnaces using services of an engineer as well as associated repair and maintenance work; Services of an industrial engineer in the filed of heat treatment, including technical design; design of heat treatment plants and industrial furnaces as well as technical consultancy in these fields